Building an absolute URL from a relative URL in Ja

Question

I'm having trouble building an absolute URL from a relative URL without resorting to String hackery...

Given

http://localhost:8080/myWebApp/someServlet

Inside the method:

   public void handleRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}

What's the most "correct" way of building :

http://localhost:8080/myWebApp/someImage.jpg

(Note, must be absolute, not relative)

Currently, I'm doing it through building the string, but there MUST be a better way.

I've looked at various combinations of new URI / URL, and I end up with

http://localhost:8080/someImage.jpg

Help greatly appreciated

Answer 1

Looks like you already figured out the hard part, which is what host your are running on. The rest is easy,

String url = host + request.getContextPath() + "/someImage.jpg";

Should give you what you need.

Answer 2

Using java.net.URL

 URL baseUrl = new URL("http://www.google.com/someFolder/");
 URL url = new URL(baseUrl, "../test.html");

Answer 3

How about:

String s = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort() + request.getContextPath() + "/someImage.jpg";